Navel orange peel hydroethanolic extract as a phytogenic feed supplement: impacts on growth, feed intake, nutrient digestibility, and serum metabolites of heat stressed growing rabbits

Abstract

Currently, using agricultural wastes in animal production has gained worldwide interest. Hence, herein, an eight-week trial was performed to explore the effects of supplemental navel orange peel extract (NPE) on the growth, feed utilization, nutrient digestibility, antioxidant, and hematological parameters of heat-stressed rabbits. In total, 75 weaned rabbits were randomly assigned into five groups. The first group was reared in the winter (mild weather) and fed an untreated pelleted diet (W-NPE-0; control). The other four groups were reared in the summer (hot climate) and fed the control diet fortified with 0 (S-NPE-0), 250 (S-NPE-250), 500 (S-NPE-500), or 1000 (S-NPE-1000) mg NPE/kg diet. The results indicated that thermal-stressed rabbits (S-NPE-0) had significantly lower feed intake, growth performance, hematological indices, serum lipid profile, and antioxidative status, but higher lipid peroxidation compared to the W-NPE-0 group. However, the highest final weight and feed intake were recorded in the S-NPE-1000 group compared with the S-NPE-0 group. Also, supplemental NPE in the growing rabbit diet, especially the S-NPE-1000 group, enhanced the hematological and antioxidative indicators. In conclusion, NPE supplementation in growing rabbit diets could be used to efficiently mitigate the detrimental effects of chronic temperature stress on performance, hematobiochemical features, and oxidative stability.